1999-12-16: KNX8073 FA20
DEPARTING ST. JOHN'S FOR MONCTON ADVISED OF PRESSURIZATION PROBLEMS AND REQUESTED TO RETURN TO ST. JOHN'S. NO EMERGENCY.AIRCRAFT LANDED RNWY
34 SAFELY AT 2137Z. NOTE
THIS AIRCRAFT EXPERIENCED SAME
PROBLEM ON 2 OTHER OCCASIONS. TSB CASE
MORE TO FOLLOW. Update: This aircraft was involved in 3 events relating to pressurization problems. One event was believed to be caused by a stuck Ground/Flight Switch.The other events were traced to a stuck Rotary Actuator in the Air supply system. The aircraft was returned to service under the provisions of the Minimum Equipment list until part availability. December 13/99 The aircraft departed St. John's and experienced another Pressurization problem. Maintenance discovered that the replacement Rotary Actuator installed earlier that day was positioned incorrectly. The valve was repositioned and the aircraft returned to service. TSB file #A99A0164.